Yarn-control mechanism for warp knitting machines



R. BASSIST YARN-CONTROL MECHANISM FOR WARP KNITTING- MACHINES May 14,.-1946.

Filed Nov. s, 1943 2 sheets sheet 1 INVENTOR Basssfi WNJOMUZ OP ATTORNEYf May 14, 1946.. R. BASSIST YARN-CONTROL MECHANISM FOR WARP KNITTINGmcxmms 2 sheets-sheet 2 Filed Nov. 3, 1945 (III/II mar-r moveo v 58 J"PATTERI? CONTROL 71 INVENTOR Patented May 14, 1946 YARN-CONTROLMECHANISM FOR WARP KNITTING MACHINES Rudolph Bassist, New York, N. Y.,assignor of forty-five per cent to himself, ten per cent to Harold K.Stern, twenty-two and one-half per cent to Edith Abrams, and twenty-twoand Edith April, all of New one-half per cent to York, N. Y.

Application November 3,- 1943, Serial No. 508,820

9 Claims.

My present invention relates generally to knitting machines and hasparticular reference to so-called warp knitting machines.

While certain phases of my invention are not necessarily restricted intheir applicability to any particular kind of warp knitting machine, thegeneral object of the invention is to provide certain improvements inhigh-speed knitting machines oi the so-called Tricot type. Thesemachines are of relatively high gauge, employing approximately 28 to 34needles per inch, and operating at rates of speed up to about 600courses or stitches per minute.

In a warp knitting machine, the yarn is initially wound on one or morewarp beams and is directed in parallel rows to a bank of needles whichoperate in a predetermined intermittent manner to interengage thethreads to produce a knitted fabric of the jersey type. The yarn isdirected to the needles by one or more guide bars through which theindividual strands are threaded and by means of which the threads arelooped around the needles or otherwise subjected to their operation, ina predetermined manner and sequence depending upon the particularpattern or style of knitted fabric which is to be produced.

In order that my invention may be better understood, I will preface thisdescription by outlining, in a general way, the mode of operation andcooperation of the main parts of a warp knitting machlne.

A main driving shaft (hereinafter referred to as a cam shaft) isassociated with means for intermittently moving the needles through theknitting cycle. Generally speaking, thi movement is an up-and-downmovement. Thread is suitably looped around the needles while they are intheir upward positions, and when the needles move downwardly theyperform a, knitting opera--' tion, with the aid of a presserbar," a"sinker," and other suitable auxiliary parts which are well known perse. Each guide baris provided with a corresponding number of needlesthrough which the strands coming from the warp beam are threaded.Actuated by the cam shaft is a means for imparting a predeterminedintermittent movement to the guide-bar, one component of movement beinga transverse or swinging movement in a substantially forward-and-backdirection, the other component of movement being longitudinal. Thesemovements of the guide-bar are so timed and controlled. relative to theneedle operation, that the strands, are suitably loop d around orotherwise subjected to the action of the needles to chine, one of theshortcomings has arisen from in accordance with a predetermined pattern.

For examplefassuming that only one warp beam is employed, the guide-barmay be moved so as to loop a strand around one needle during one course,around an adjacent needle during the next course, and so on. Or,depending upon the fabric desired, the guide-bar may loop a stranddirection to loop the strand around a third selected needle for thethird". course, and so on. A

large number of different optional cycles are possible, depending uponthe results desired in the finished product. In each case. however, thelongitudinal movement of the guide-bar requires that a certain amount ofyarn be made available to it, the exact amount being dependent upon theextent of the longitudinal movement of the guidebar; and during eachforward-and-back or swinging movement of the guide-bare. relativelyreduced amount of thread should be made available to it. The greater theaccuracy with which the yarn feed corresponds to the moment-tomomentfluctuating yarn demands of the guidebar. the more smoothly andemciently will the machine operate.

' The machine may employ either one, two or three warp beams, possiblymore. The simplest type of fabric is produced by the employment of' onlya single warp beam. A different type of fabric would result from theemployment of two warp beama itibeing understood that there is usually aseparate guide-bar for each warp beam. Where a ."filler" thread, or moreaccurately, an

unknitted warp thread, is to be associated with the fabric for thepurpose of forming loops or and to the strands of the ground fabric, ina predetermined manner.

For the sake of simplicity, the features of the present invention willbe described in connection with a single warp beam and a singleguidesbar. although it will be understood, as hereinbefore pointed out.that mor than one warp beam may be employed if necessary or desirable.

In the conventional type of warp knitting mathe fact that the threadsare drawn from the warp beam by a pulling action initiated by theneedles themselves and by the guide-bar which controls the dispositionof the yarn with respect to the needles. The warp beam is generallyprovided withsome sort of brake equivalent clutch mechanism operated bythe pull of the yarn, whereby the warp beam is released for rotationwhenever the knitting cycle call for thread, and whereby it is securedagainst rotation in the interim periods. This arrangement has numerousdisadvantages and imposes severe limitations upon the knittingoperations. For example, the interdependence between yarn feed and warpbeam rotation restricts the types of fabric that may be produced. Also,any stoping or starting of the machine as a whole produce anirregularity in the knitting operation whereby an undesirable line orstreak known as a stop-mark is produced in the fabric. The latterdisadvantage often causes material impairment of the commercial value ofthe fabric, and it manifests itself most frequent in the highspeedmachines to which my invention has primary reference, and in cases wherethe yarn is of the relatively slippery character of rayon or the like.

In my Patent No. 2,303,903, I disclosed a means whereby thesedisadvantages, and others, are successfully overcome, one of thecharacterizing features of the improved machine residing in the factthat the warp beam is continuously rotated in yam-feeding direction in apredetermined timed relationship with respect to the knitting cycle, butindependent of any pulling action upon or by the yarn itself.

In my Patent No. 2,334,058, I described a further improvement andrefinement of this general type of machine, whereby there is imposedupon a continuously rotating warp beam a regular fluctuating componentof movement intended to synchronize the thread feed with the fluctuatingrequirements ofthe needles and guidebars. I disclosed the employment inthe warp beam transmission, of a mechanism (exemplified by a pair ofmeshing non-circular gears) which comprises rotating driving and drivenmembers wherein a fluctuating angular velocity is imparted to the drivenmember relative to that of the driving member.

In my Patent No. 2,361,526, I described certain further improvements bymeans of which an even wider range of adjustments wa provided for in thetiming of the thread feed and'its synchronization with the yarnrequirements of the guidebars and needles.

- It is the principal object of the present invention to provide certainfurther refinements in this general type of warp knitting machine.whereby further accuracy of synchronization may be effected, whereby thesmoothness and efficiency of operation, even at relatively high speedsand for protracted periods, may be enhanced, and whereby there may beprovided in a warp knitting machine, operating as hereinbeforedescribed, a delicately controlled automatic stop mechanism designed tohalt the machine in case of thread breakage or thread failure.

One feature of the present improvement consists, in brief, of anadjustable mechanically-operated'means for takin up d releasing. in apredetermined manner, the thread which is being fed from the warp beamto the knitting instrumentalities. This is not to be confused,howtake-up, because obviously no such continuous take-up or threadtensioning may be employed in a machine, like the present, in which thethread is positively fed or directed from the warp beam to the needles,as distinguished from a machine or mode of operation in which the threadfeed is brought about by a pulling action upon the thread.

The present mechanically-operated thread take-up and release mean iscontrolled and driven by the cam shaft of the machine or by any othersuitable driving instrumentality operating in timed relation to the maindrive. It is to be understood that the term mechanically-operated"includes within its significance any electrical, magnetic, or othermeans of actuation and is intended merely to signify a positive type ofoperation as distinguished from the purely negative and continuousaction of an ordinary springever, with any ordinary type of resilientslack actuated or otherwise resiliently-controlled mechanism.

The advantages of this improvement will be pointed out hereinafter, andreference will be.

made to some of the circumstances under which it is intended to beemployed.

Another improvement forming part of the present invention appertains tothe automatic stopping of the machine in case of thread breakage orthread failure. Its usability and advantages are directly attributableto the mechanical thread take-up and release means hereinbeforementioned, because of the leveling effect of the latter upon undesiredtransverse thread movements or vibrations. So far as I am aware, anautomatic stop mechanism of the present character has never before beenemployed or even deemed to be applicable in a warp knitting machine.Briefiy, the present improved structure consists of a delicately-poisedfeeler associated with each thread in such a manner that thread breakageor failure automatically disturbs the balance so as to effect aninstantaneous stoppage of the machine.

I achieve the foregoing general objects and advantages, and I providefor the embodiment of the tion of Figure 4 and Figure 6 is a.diagrammatic view showing the relationship between certain driving anddriven parts of the machine and certain electrical controls.

I have omitted a showing of a warp knitting machine as a whole, sincethe present invention may be adequately described and illustrated byitself. The general type of warp knitting machine to which my inventionrelates is illustrated in Figures 1, 2 and 3 of my aforementioned PatentNo. 2,334,058. Briefly, the machine is provided with a bank of needlesand at least one guide-bar which cooperates with them-in performing theknitting operations. The needles are intermittently moved in a generalup-and-down direction,

. my aforesaid patent.

the motive power being derived from a main driving shaft or cam shaft.The guide bar has two types of movements, one of which is a swinging orback-and-forth movement, the other of which is a reciprocatorylongitudinal movement. Both of these movements are brought about by themotive power of the cam shaft. the swingingmovement being generallyaccomplished by an articulation of parts as shown in Figure 2 of myaforesaid patent, the longitudinal movements being effected with the aidof a pattern wheel or similar instrumentality such 'as that shown inFigures 1 and 4 of said patent. The machine is also provided with atleast one warp beam which is positively driven by a transmission whichderives its power from the cam shaft. In the preferred embodiment, thistransmission includes a change-speed device, whose general nature andmode of operation are well known per se, such a device being illustratedin considerable detail in The change-speed device has a driving shaftand a driven shaft, and is also provided with an adjustable member orrod whose operation alters the relation between the angular velocitiesof the driving and driven shafts.

Referring now to Figure 1 of the present drawings, the cam shaft of themachine is designated by the reference numeral Ill, and I haveillustratlvely shown a thread H which is travelling from right .to leftas viewed in Figure 1. This thread may be assumed to be emanating fromthe warp beam (not shown) and to be advanced ultimately to the needlesand guide-bar. It will be understood that a multiple number of suchthreads are travelling atone time in the manner indicated. Thus, while Ihave shown a single thread ii in Figure 2, and have shown it passingbetween two adjacent upstanding teeth l2 of a comb it, it will beunderstood that a. similar thread is simultaneously travelling througheach pair of adjacent teeth l2.

' will serve to take. up and release a predetermined amount of slack inthe thread or yarn. In accordance with my invention, and for purposeswhich will hereinafter be described in greater detail, this take-up andrelease of slack is caused to occur in a predetermined manner duringeach 1 knitting cycle. By knitting cycle I refer to one Thepositively-driven or mechanically operated mechanism for taking up andreleasing yarn, in accordance with my present invention, may assumevarious forms. A relatively simple embodiment is shown in Figure 1 andconsists of an oscillating member l4 mounted for pivotal movement uponthe shaft II which extends longitudinally across the machine. The memberI4 is in effect a lever of the first class, and it is intended to rockupon the shaft I! as a pivot. The rearward arm of this lever is providedat its end with a follower or roller 18 which is held by means of aspring I! in contact with a cam l8 mounted upon the jack shaft ID. Thelatter shaft is continuously rotated by any suitable transmissionoperating in timed relation to' the main'drive of the machine, and Ihave illustratively shown sprocket wheels 20 and 2! mounted upon theshafts, l8 and I0, respectively, and a chain 22 which extends aroundthese sprocket wheels.

The forward arm of the lever l4 serves as a carrier for at least onethread-guide member or roller, and I have illustratively shown apreferred construction in which there are two such members 23 and 24.These members are intended to cooperate with similar guidin members orrollers 25, 28 and 21. All of these guiding members extendlongitudinally across the machine so that all the threads pass over andunder them, as shown in Figure 1. The members 25, 2t and 21 arepositionally fixed. while the members 23 and 24 are relatively movable.75

complete cycle of operation of the needles and guide-bar, whereby onecourse of the resultant fabric is produced.

The relatively movable guide members 22 and 24 may be secured to thecarrier l4 in any desired manner, but I have found it preferable toemploy a resilient securing means. Thus, it will be observed that eachof the members and 24 is mounted upon a shaft 28 journaled in bearings2! which are constantlyurged downwardly by means of a spring 3!. Thisspring exerts its compressing force against a collar or shoulder 3isecured to the journal 29, and against a rel-' atively fixed shoulder 32which is secured to the carrier H by means or a stud or similaradjustable fastening device 33. By adjusting the latter, the shoulder 32may be shifted by slight amounts toward or away from the shaft 28,thereby effecting a corresponding increase, or decrease in thecompressive power of thesprlng 30. This spring is purposely made of sucha strength that it will not yield to I any appreciable extent when theguiding members 23 and 24 move downwardly (as viewed in Figure 1) totake up slack in the thread, otherwise the oscillating movements of thelever l4 would fail to fulfill the desired securement of the members 23and 24 in the carrier arm, and it will be understood that these springsmay under certain circumstances be dispensed with entirely.

In Figure 3 I have illustrated the possibility of effecting the desiredtake-up and release of slack by a slightly different type of mechanismwhich is positioned in its entirety below the level of the threadstravelling forwardly across the machine from the warp beam to theneedles. An oscillating member .or carrier I4 is in this case similarlymounted for pivotal oscillations on the shaft 25, and the rear arm isactuated by means of a'follower or cam (or equivalent mechanism) similarto the elements I! and II of Figure 1. The forward arm of the lever 34is provided with an arcuate member-tithe are being concentric with thepivot Carried by the memher I! are a plurality of fingers 31, each ofshaft or pivot 22.

Coniointly, the fingers 81 define at their outer ends 'an arcuate guideover which the threads '40 arecaused to travel on their way to theneedles. A rocking movement of the lever 24 serves intermittently toincrease and decrease the radius of this composite outer guidingsurface, whereby a predetermined amount of slack may be taken up andreleased during each knitting cycle.

For the sake of simplicity of description, each of the oscillatablemembers 14 and 34 of Figures 1 and 3 has been shown in the form of alever whose lever arms are of predetermined relative lengths. In eachcase, the shape and contour of the cam (or equivalent instrumentality)which causes the oscillations will determine the amount or magnitude ofmovement of the guiding members which take up and release the slack inthe thread. In the preferred embodiment of my invention, however, therelative lengths of the lever arms are adjustable or variable during acontinued operation of the machine as a whole, so that the magnitude ofthe thread take-up may be accurately varied in accordance with apredetermined plan or pattern, in a corresponding manner. To accomplishthis result, the pivoted lever or carrier member is preferably formed asshown at the left of Figure 4 and is associated with an adjustable leveror mechanism as shown most clearly in this figure.

In Figure 4, the shaft H is intended to represent the shaft .l5 ofFigure 1 or the shaft 35 of Figure 3, and the reference numeral 42 isapplied to the rear lever arm of the oscillating carrier member. Itmakes no difference whether the forward portion of the member 42 isconstructed as in Figure l, or as in Figure 3, or in any other desiredmanner, but it will be observed that the rear arm is provided with alongitudinal groove or slot 43' within which a roller 44 is' arranged.This roller is mounted at. the forward end of a rod 45 which isexteriorly screw-threaded as at 45 and which extends into a suitablebore 41 in the oscillatable member 48. The latter is mounted for pivotalor oscillative movements upon a shaft 49 and is provided at its rear endwith a follower 50 which rides upon an actuating cam 5|, a spring 52serving to keep the follower 50 in contact with the cam 5|. The cam 5|corresponds to the cam I8 of-Figure 1, and is constantly rotated ordriven by a suitable transmission from the cam shaft of the machine.

Mounted upon the member 48 is a reversible motor 53 which carries on itsshaft a small driving pinion 54. This pinion meshes with a relativelylarge gear 55 which is provided at its hub with a worm 58 engaging thethreads 46 on the rod 45. The member 48 is suitably recessed as at 51 toaccommodate the gear 55.

In a manner and for a purpose presently to be described, the motor 53 iscaused to operate at predetermined times, either in one direction or theother, so as to impart a corresponding rotation to the gear 55. Throughthe intermediary of the worm 56 and the threads 46, this brings about acorresponding longitudinal movement of the rod 45 into or out of thebore 41, thus slightly reducing or slightly increasing the effectivelength of this rod, When the rod is shortened, the magnitude of theoscillatory movements of the roller 44 is slightly reduced, thusbringing about a corresponding reduction in the magnitude of oscillatingmovement of the member 42 and thus in turn bringing about acorresponding reduction in the magnitude of slack which is taken up andreleased. When the rod 45 is slightly lengthened, the magnitude ofoscillating movement of the roller 44 is correspondingly increased by aslight amount and this in turn brings about a correspondingly increasedoscillation of the member 42, and a corresponding increase in themagnitude of the slack which is taken up or released. This adjustabilitymay be eil'ected during a continued operation of the machine, since itis entirely independent of the contour or relative proportions of thecam 5| The purposes and advantages of the present mechanism forpositively taking up and releasing certain amounts of slack during eachknitting cycle can best be described by reference to several specificillustrative circumstances.

(1) As has been pointed out, the mode of operation of a warp knittingmachine is of such a character that during each knitting cycle arelatively large amount of thread may be required during one interval oftime, While a relatively smallamount of thread may be required during asucceeding length of time. Thus, while the guide-bar is movinglongitudinally, a relatively large amount of thread may be required,while the transverse or swinging movement of the guide-bar (to loop thethread around a predetermined needle) usually requires a lesser amountof thread. In as much as the basic feature of the'present type ofmachine lies in the fact that the thread is positively directed towardthe needles by an independent actuation of the warp beam, .i.- e., by anactuation which is entirely independent of any pull exerted by needlesor guidebar, it ,is important that proper amounts of thread be fed tothe guide-bar and needles in accordance with their momentaryrequirements. The more accurately the thread feed is synchronized withthe moment-to-moment requirements of the guide-bar and needles, the moresmoothly will the machin operate, especially at high speeds.

Assuming, therefore, that in the simplest type of machine there is adirect connection between the cam shaft and the warp beam (with perhapsa speed reducer or the like and possibly a changespeed device, but withno special mechanism such as the non-circular gears illustrated in myaforementioned Patents Nos. 2,334,058 and 2,361,- 526, it is obviousthat the thread from the warp beam will be fed toward the needles at auniform rate. As hereinbefore explained, however, the knitting cycledoes not utilize thread at this uniform rate, and during each knittingcycle there is a momentary call for a larger amount of thread and asucceeding call for a smaller amount. This variation during eachknitting cycle can be taken care of by means of the presentmechanically-operated slack take-up so that the amount of threadavailable to the guide-bar and needles is accurately in synchronism withthe requirements of the knitting cycle.

(2) As a second illustrative circumstance under which the presentmechanical take-up device may be employed, let it be assumed that thetransmission from the cam shaft to the warp beam includes a set ofnon-circular gears, such as the elliptical gears illustrated anddescribed in each of my aforesaid Patents Nos. 2,334,058 and 2,381,526.These gears, similarly, serve the function of setting the tempo," as itwere, of the thread feed to synchronizeit with the knitting cycle. Itmay happen, however, that because of manufacturing limitations thetheoretical design of these non-circular or elliptical gears cannot beaccurately carried out during the manufacturing process, especiallywhere the machine is to operate at high speeds. As a result,thenon-circular gears (or equivalent mechanism) may prove to be slightlydeficient in feeding the thread to the needles and guide-bar in exactlythe accurate the machine or during its operation, that the variations inthread feed which are brought about by the non-circular gears orequivalent mechanism will be augmented or diminished, as the case maybe, to the accurate amount desired.

brought into engagement with the fixed electric contact 5!.

(3) A third situation of similar kind may present itself where therotation of the warp beam is regulated by a, special pattern control,such as the pattern chains shown in Figures 7 and 8 of my Patent No.2,334,058, or the pattern control wheel shown in Figure 2 of my PatentNo. 2,361,526. Here again, the limitations or special requirements ofthe manufacturing process may cause such pattern control to deviateslightly from the desired theoretical. For example, smooth operation athigh speeds may require that the steps on the pattern control wheel. bemerged more gradually with one another so as to avoid movements of tooabrupt a character. Under such circumstances, the present mechanicaltakeup mechanism may be employed as an auxiliary means to compensate forsuch deviation.

(4) A fourth situation under which the'present mechanism may prove to beuseful arises from the possible use of two or more guide-bars, each oneregulating the manner in which thread from a separate warp beam isinterengaged with the needles or with the threads of a ground fabric.

These guide-bars are arranged one behind the during that portion of theknitting cycle when it is again required.

The automatic regulation of the take-up, during continued operation ofthe machine, in accordance with the illustrative mechanism shown inFigure 4, may find utility under circumstances such as thoseillustratively shown in Figure 6. In this figure, I have illustrativelyshown a pattern-controlling mechanism similar to that shown in Figures 7and 8 in'my Patent No. 2,334,058. A continuously travelling chain orchains (not shown) causes rods 58 and 59 to be individually moveddownwardly at predetermined times. Downward movements of the rod 58cause a lever (pivoted at 8|, to move into the illustrative positionshown in Figure 6, in which the electric contact 62 (carried by thelever 60) is brought into engagement with the relatively fixedelectrical contact 63. When downward pressure on the rod 5 8 isreleased, a spring 54 restores the rod 58 to its upward position andbreaks the contacts 82, 63. Similarly, downward movement of the rod 59causes a similar pivotal movement of the lever 65 which is pivoted at 58and which carries an electric contact 51. The lever 65 is held in itsnormal position-by the spring BI, and when it is pivoted by the rod 59,the contact 61 is which derives its'power from the cam shaftof Theseelectric contacts are arranged in a circuit which regulates a reversibleelectric motor I0. That is, when all contacts are broken, the motor I0is idle and does not operate; when the contacts 62, 83 are inengagement, current from a suitable source II passes through the motorI0 to rotate it momentarily in one direction; and when the contacts 61,69 are in engagement, current passes through the motor Hi to rotate itmo mentarily in the opposite direction.

The motor I0 may have its shaft I2 connected to the change-speed controlof a change-speed device I3. This device has an input shaft I4 theknitting machine (either directly or through an intermediarytransmission) and the output or driven shaft I5 may be connected througha speed reducer I5 to the warp beam 11.

This illustrative transmission, and the electric circuit shown,issubstantially the same as the corresponding mechanism and partsillustrated and described in my Patent-No. 2,334,058, and ailords ameans whereby the continuous rotation of the warp beam may be slowed orspeeded up during continued operation of the knitting machine, inaccordance with a predetermined plan or pattern. Obviously, when thewarp beam is speeded up, a larger amount of thread is fed to the needlesduring each knitting cycle, and when the warp beam is slowed, arelatively smaller amount of thread is fed to the needles durin eachknitting cycle. Accordingly, the amount of slack to be reckoned with isslightly larger in one case than in the other, and for this reason it isdesirable that the present slack take-up and release mechanism beautomatically regulated as indicated in Figure 4, during continuedoperation of the knitting machine. This automatic regulation ispreferably accomplished by connecting the motor 53 (Figure 4) with theelectrical circuit of Figure 6, so that the motors 53 and in arearranged in parallel and operate together. That is, when the motor I0 isidle, the motor 53 is also idle; when the motor l0 momentarily rotatesin one direction, the motor 53 does the same; and when the motor 10momentarily rotates in the opposite direction, the motor 53 does thesame,

for stopping the machine in case of an interruption oi. continued yarntravel. The means by which I prefer to accomplish this result is shownmost clearly in Figures 1 and 2.

As hereinbeiore described, each thread II passes through two adjacentteeth l2 of a comb I3. Adjacentto this comb is a similar comb I8provided with spaced partitions or teeth IS. The comb I8 is providedwith a supporting ridge, adapted to support, in delicately poisedpositions, a plurality of make-and-break contact members 8|. It will beunderstood that there is onegof these members between each pair ofadjacent partitions 19, although only one such member is shown inFigures 1 and 2.

The member 8| has a curved portion 82 which rests upon the ridge 80, anda forward arm 83 which is adapted to press upwardly against the threadThe' rearward arm 84 is preferably composed of insulating material andcarries an electric contact element 85 positioned in operative relationto a pair of bus-bars or electric contact members 86. The members 88 aresuitably arranged in an electrical circuit which controls the cam shaftof the knitting machine, the arrangement being such that theestablishment of a short-circuit between the members 86 will affect theelectrical circuit in such a manner as to discontinue the operation ofthe cam shaft.

Under normal circumstances, each of the make-and-break devices 8| ispoised in the position shown in Figures 1 and 2, whereby the contactelement 85 is inoperative so far as the contact members 85 areconcerned. So long as the thread continues to travel in an uninterruptedmanner, its downward pressure on the forward 'arm 83 holds the element85 in the normal inoperative position. The device 8| is so weighted,however, that if the thread breaks or fails, or for any other reasondiscontinues its pressure upon the arm 83, the device 8| will swingimmediately into a position in which the contact element 8'5short-circuits the members 88. After the machine has stopped, and afterthe operator has remedied the cause of'thread failure or inneedles and aguide-bar operated thereby, a warp beam, means independent of any pullexerted by needles or guide-bar for feeding yarn from the warp beam tothe needles, an adjustable oscillatable member.actuated by the cam shaftin timed relation to the needle'and guide-bar operation for taking upand releasing slack in said yarn during each knitting cycle, and meansfor adjusting said member to vary the magnitude of its oscillations andthereby vary the magnitude of said slack take-up and release, saidoscillatable member comprising a pivoted lever and said adjusting meanscomprising a mechanism for altering the relative lengths of its leverarms.

4. In a, warp knitting machine, a cam shaft, needles and a guide-baroperated thereby, a warp beam, means independent of any pull exerted byneedles or guide-bar for feeding yarn from the warp beam to the needles,means operable during continued operation of the machine for varying theamount of yarn feed in accordance with a predetermined plan, adjustablemechanism actuated by the cam shaft in timed relation to the needle andguide-bar operation for taking up and releasing slack in said yamduringeach knitting cycle, and means operating in timed relation to saidyarn-feed-varying means for adjusting said a mechanism during continuedoperation of the terruption, the machine is ready to resume operation.

It will be understood that, for the sake of clarity, the presentdrawings are in man respects exaggerated and diagrammatic, and thedetails of structural proportions are not accurately depicted.

It will also be understood that the details herein described andillustrated are given merely by way of example, and that changes mayreadily be made by those skilled in the art without departing from thespirit and scope of the invention as expressed in the appended claims.

Having thus described my invention and illustrated its use, what I claimas new and desire to secure by Letters Patent is: I

1. In a warp knitting machine, a cam shaft,

needles and a guide-bar operated thereby, a warp beam, means independentof any pull exerted by needles or guide-bar for feeding yarn from thewarp beam to the needles, adjustable mechanism actuated by the cam shaftin timed relation to the needle and guide-bar operation for taking upand releasing slack in said yarn during each knitting cycle, and meansfor adjusting said mechanism during continued operation of the machineto vary the magnitude of said slack take-up and release.

2. I a warp knitting machine, a cam shaft, needles and a guide-baroperated thereby, a warp beam, means independent of any pull exerted byneedles or guide-bar for feeding yam from the machineto vary themagnitude of said slack takeup and release.

5. In a warp knitting machine, a cam shaft, needles and a guide-baroperated thereby, a warp beam, means independent of any pull exerted byneedles or guide-bar for feeding yarn from the warp beam to the needles,and mechanism actuated by the cam shaft in timed relation to the needleand guide-bar operation for taking up and releasing slack in said'yarnduring each knitting cycle, said mechanism comprising relatively movableguiding members over which the yarn travels, and means for effectinganintermittent relative movement of said members.

6. In a warp knitting machine, a cam shaft, needles and a guide-baroperated thereby, a warp beam, means independent of any pull exerted byneedles or guide-bar for feeding yarn from the warp beam to the needles,relatively movable guiding members over which the yarn travels, at leastone of said members being positionally fixed, at least one other of saidmembers being relatively movable, and mechanism for intermittentlymoving the latter, said mechanism being actuated by the cam shaft intimed relation to the needle and guide-bar operation whereby saidintermittent movement takes up and releases slack in said yarn duringeach knitting cycle.

7. In a warp knitting machine, a cam shaft, needles and a guide-baroperated thereby, a warp beam, means independent of any pull exerted byneedles or guide-bar for feeding yam from the Warp beam to the needles,relatively movablev guiding members over which the yarn travels, atleast one of said members being positionally fixed,

at least one other of said members being relatively movable, anoscillatable carrier for the latter, and mechanism for oscillating saidcarrier, said mechanism being actuated by the cam shaft in timedrelation to the needle and guide-bar operation whereby said oscillationtakes up and releases slack in said yarn during each knitting cyc e.

8. In a warp' knitting machine, a cam shaft, needles and a. guide-baroperated thereby, a warp beam, means independent of any pull exerted byneedles or guide-bar for feeding yarn from the warp beam to theneedles,- relatively v movable guiding members over which the yarntravels, at least one oi said members being positionally fixed, at leastone other or said members being relatively movable, an oscillatablecarrier Ior said movable member, yieldable resilient means securing saidmember to said carrier, and mechanism for oscillating said carrier, saidmechanism being actuated'by the cam shaft in timed relation to theneedlenand guide-bar operation whereby said oscillation takes up andreleases slack in said yarn during each knitting cycle.

9. In a warp knitting machine, a cam shaft, needles and a guide-baroperated thereby. a warp beam, means independent oi any pull exerted byneedles or guide-bar for feeding yarn from the warp beam to the needles,relatively movable guiding members over which the yarn travels, at leastone of said members being positionaliy fixed,

at least one other of said members beinarelatively movable, anoscillatable carrier for said movable member, yieidable resilient meanssecuring said member to said carrier, mechanism for oscillating saidcarrier, said mechanism being actuated by the cam shaft in timedrelation to the needle and guide-bar operation whereby said oscillationtakes up and eleases slack in said yarn during each knitting cycle, andmeans for adjust ing the resilience of said resilient securing means.

RUDOLPH BASSIST.

